On my return, once I have cleared customs and collected my bags, I call the shuttle number indicated in my confirmation email, to inform my shuttle driver that I am waiting for him at the meeting point.
The shuttle arrives at the meeting point at the time indicated on my reservation, the shuttle driver helps me load my luggage and brings me back to the car park to collect my vehicle, where I collect my keys on presentation of an ID document.
If I arrive at the meeting point earlier or later than the time noted in my reservation, I may have to take the next shuttle.